feat: integrate retrieval service v1 in Python SDK

[suguanYang]

Summary

Adds Python SDK support for the new retrieval-service v1 API surface introduced by knowhere-api#204.

This PR depends on https://github.com/Ontos-AI/knowhere-api/pull/204, which is not merged yet, so live compatibility was verified against a local API checkout of that branch.

Client-facing changes

• Adds client.retrieval.query(...) and async_client.retrieval.query(...) for POST /v1/retrieval/query.
• Adds client.documents.list(...), client.documents.get(...), client.documents.archive(...) and async equivalents for /v1/documents lifecycle APIs.
• Extends jobs.create(...) and parse(...) with namespace and document_id so callers can create retrievable documents and update existing documents.
• Extends Job and JobResult models with namespace and document_id.
• Adds typed response models for retrieval results, citations, documents, and document lists.
• Updates README and usage docs with caller workflows for create, update, query, exclusions, list/get/archive.

Local verification

SDK checks:

uv run pytest
uv run ruff check .
uv run mypy src

Results:

• 224 passed
• ruff: all checks passed
• mypy: no issues found in 25 source files

Live local compatibility smoke against unmerged knowhere-api#204:

• API checkout: feat/wangbinqi/retrieval-service-v1 at bd391ef
• Local API base URL: http://127.0.0.1:5005
• Local DB: knowhere_e2e_will_204
• Namespace: e2e-will-204-nokia
• Document: doc_da46b74e3b83

Verified through the SDK:

• sync client.retrieval.query(namespace="e2e-will-204-nokia", query="Bluetooth", top_k=3) returned 3 results from the Nokia PDF document
• sync client.documents.list(namespace="e2e-will-204-nokia") returned the active Nokia document
• sync client.documents.get("doc_da46b74e3b83") returned the active document state
• async client.retrieval.query(...) returned the Nokia document result
• async client.documents.list(...) returned the Nokia document list

Note: because knowhere-api#204 is unmerged, this PR should be revalidated after the API PR lands or if its public contract changes before merge.